[Eeglablist] Correcting skin potential artifact for ERP studies

[周云晖]

Dear colleagues,

I am trying to analyze visual event related potentials (ERP) from some EEG data, but a few subjects showed quite long period of skin potential artifacts throughout the experiment. We previously removed 
most of these artifacts by high-pass filtering at 1 Hz, but now for ERP analysis I set the cut-off frequency at 0.1 Hz. After epoching (900 ms long) I see lots of epochs with baseline drift. 

I found that many epochs with such drift can be corrected by linear detrending, and some may need further correction by parabolic detrending, but I am not sure how this will affect the ERP shape. Or 
I can reject all the epochs with such drift, but that means significant data loss for these subjects. 

The data was recorded by actiCHAMP (Brain Products) with 64 active electrodes, and we lowered the impedance of all electrodes to below 10 kOhm. The experiment was performed recently in winter and the room
was cool and dry. I hope some experts in ERP can give me some suggestions on dealing with skin potentials.

Thanks,

Zhou